Which of the following medications is often prescribed for hypertension?

Hydrochlorothiazide is a thiazide diuretic commonly prescribed to manage hypertension, or high blood pressure. It works by increasing urine output, which helps reduce fluid in the blood vessels and lowers blood pressure. By inhibiting sodium reabsorption in the kidney, this medication effectively helps relax blood vessels, further contributing to lowering blood pressure levels.

The other medications listed serve different purposes: Aspirin is primarily used for its anti-inflammatory and antiplatelet effects, Erythromycin is an antibiotic used to treat bacterial infections, and Ampicillin is also an antibiotic used for infections. None of these are indicated for the treatment of hypertension, making Hydrochlorothiazide the appropriate choice for this condition.